Iquique Articulated Locomotives in Peru


Class Details by Steve Llanso of Sweat House Media

Class Tarapaca (Locobase 14821)

Data from "Fairlie Locomotive 'Tarapaca'", Engineering, Vol 10 (19 August 1870), pp. 141-142, and 16 September 1870), pp. 201-202. See also "A New Locomotive Engine," Brisbane (Australia) Observer, 10 October 1870, p.4, (originally published in the Times of London) archived at [link], last accessed 8 January 2013. See also "The Salpetre Deposits of Peru" from Journal of the Society of Arts, Van Norstrand's Eclectic Engineering Magazine, Vol XIV, No LXXXVIII (April 1876), p. 324.

The Engineering articles go into considerable detail, the 19 August entry saying in summary: "The general design of the engine is excellent, and notwithstanding its large size, there is nothing whatever about it suggestive of clumsiness, and much less of unwieldiness."

The report does not spell out exactly how the pipe connecting the two steam domes works, but one supposes it balanced steam pressure between the two cylinder sets. Fairlies had a pair of fireboxes placed back to back on the left side of the center of the frame. Each firebox heated an identically sized boiler that had 130 tubes. The central axle of each of the two bogies was positioned directly under the bogie pin.

Engjneering reported that the Iquique line (which later lay in Chile after the War of the Pacific) had very steep gradients that included one run of 11 miles (17.7 km) at a constant 1 in 26 (just under 4%). The Tarapaca was expected to pull 150 tons up this grade at 11 mph (17.7 km/h). The report said the Tarapaca ran "easily and rapidly" around the test railway at Fairlie's Hatcham Works, which included two curves with radii of 50 feet (15.2 metres).

See the breezy challenge offered by American engineer W W Evans to the claims made for the Tarapaca in the 11 November 1870 issue, p. 347 and another detraction in "Fairlie Engines", Engineering, Volume , (14 December 1877), pp. 462-463.

Principal Dimensions by Steve Llanso of Middle Run Media
ClassTarapaca
Locobase ID14821
RailroadIquique
CountryPeru
Whyte0-6+6-0T
Number in Class1
Road Numbers
GaugeStd
Number Built1
BuilderFairlie
Year1870
Valve GearAllan
Locomotive Length and Weight
Driver Wheelbase (ft / m) 7.67 / 2.34
Engine Wheelbase (ft / m)27.92 / 8.51
Ratio of driving wheelbase to overall engine wheelbase 0.27
Overall Wheelbase (engine & tender) (ft / m)27.92 / 8.51
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)134,400 / 60,963
Engine Weight (lbs / kg)134,400 / 60,963
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)2640 / 10
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 2.20 / 2
Minimum weight of rail (calculated) (lb/yd / kg/m)37 / 18.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)42 / 1067
Boiler Pressure (psi / kPa)145 / 1000
High Pressure Cylinders (dia x stroke) (in / mm)15" x 20" / 381x508 (4)
Tractive Effort (lbs / kg)26,411 / 11979.84
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.09
Heating Ability
Tubes (number - dia) (in / mm)260 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)10.79 / 3.29
Firebox Area (sq ft / m2)125 / 11.61
Grate Area (sq ft / m2)21 / 1.95
Evaporative Heating Surface (sq ft / m2)1625 / 150.97
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1625 / 150.97
Evaporative Heating Surface/Cylinder Volume198.63
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation3045
Same as above plus superheater percentage3045
Same as above but substitute firebox area for grate area18,125
Power L12791
Power MT274.69

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